Field of the Invention
The present invention relates generally to the field of gear systems and more particularly to a modular gear system which includes a contrate gear.
Modular gear systems are typically formed by connecting various gear modules and drive modules to one another to form a gear drive unit which matches the requirements of a given application.
In prior art modular gear systems, the angular gears represent particularly complex components. An additional gear stage with bevel toothing or a worm wheel set is generally provided. In the case of combined bevel and spurgears, an at least two-stage transmission is therefore obtained since there is an input spur wheel set connected to the input of the bevel wheel set and possibly another spur wheel set connected to its output in order, at least to this extent, to standardize its construction with gear modules of a different design. It is likewise always possible for a worm wheel set to be placed ahead of a spur wheel set, for which reason there is often an at least two-stage transmission in this case. Very large transmission ratios can be achieved with such a two-stage transmission of a worm wheel gear.
Contrate gears are also known, which are likewise angular gears and in which a cylindrical pinion interacts with what is referred to as the contrate gear. A gear of this kind is described in the German periodical "antriebstechnik" (Drive Technology), 33 (1994) No. 11, in an article entitled "Cylkro-Getriebe--eine neue Herausforderung" (Cylkro gears--a new challenge). The contrate wheel of such a gear can be described as a rack curved in the form of a circle, the teeth of which are arranged either parallel to the plane of the circle or obliquely to it, the associated cylindrical pinion having a constant geometry along its tooth width and therefore also being immediately suitable for engagement in customary spur wheel toothing. Particularly if a suitable diameter for the contrate wheel is chosen, the contrate wheel gear offers the advantage of a large transmission range, axial freedom of the pinion and any angle of the axes.